Ramping well bores

• US 6,725,922 B2
• Filed: 07/12/2002
• Issued: 04/27/2004
• Est. Priority Date: 07/12/2002
• Status: Expired due to Fees

• Current Assignee: Effective Exploration LLC
• Original Assignee: CDX Gas LLC (EnerVest Ltd.)
• Inventors: Zupanick, Joseph A.
• Primary Examiner(s): KRECK, JOHN J
• Application Number:
  US10/194,367
• Publication Number:
  US 20040007352A1
• Time in Patent Office: 655 Days
• Field of Search: 175/61, 175/62, 166/245, 166/50, 166/313, 166/52
• US Class Current: 166/245
• CPC Class Codes: E21B 41/0064 Carbon dioxide sequestration storing fluids in porous layers B65G5/005
• CPC Class Codes: E21B 43/305 comprising at least one inclined or horizontal well
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

In accordance with one embodiment of the present invention, a subterranean drainage pattern for accessing a subterranean zone includes a main well bore extending from a surface well bore, located at a first end of the area, to a second end of the area. A first plurality of lateral well bores extend in spaced apart relation to each other from the main well bore to the periphery of the area on a first side portion of the main well bore. A second plurality of lateral well bores extend in spaced apart relation to each other from the main well bore to a periphery of the area on a second, opposite side portion of the main well bore. A first plurality of ramping well bores extend in spaced apart relation to each other from the main well bore toward a boundary of the subterranean zone.

Claims

1. A subterranean drainage pattern for accessing an area of a subterranean zone comprising:

a main well bore extending from a surface well bore located at a first end of the area to a second end of the area, the main well bore traversing a substantially horizontal plane;

a first plurality of lateral well bores extending in spaced apart relation to each other from the main well bore to the periphery of the area on a first side portion of the main well bore, wherein the length of each of the lateral well bore progressively shortens as a distance between a respective lateral well bore and the surface well bore increases;

a second plurality of lateral well bores extending in spaced apart relation to each other from the main well bore to a periphery of the area on a second, opposite side portion of the main well bore, wherein the length of each of the lateral well bore progressively shortens as a distance between a respective lateral well bore and the surface well bore increases; and

a first plurality of ramping well bores extending in spaced apart relation to each other from an upper portion of the main well bore, the first plurality of ramping well bores extending in a substantially vertical plane toward an upper boundary of the subterranean zone; and

a second plurality of ramping well bores extending in spaced apart relation to each other from a lower portion of the main well bore, the second plurality of ramping well bores extending in a substantially vertical plane toward a lower boundary of the subterranean zone.

2. The subterranean drainage pattern of claim 1, wherein the subterranean zone comprises a single layer of hydrocarbons.

3. The subterranean drainage pattern of claim 2, wherein the single layer comprises a coal seam.

4. The subterranean drainage pattern of claim 1, wherein the subterranean zone comprises a plurality of layers of subterranean deposits separated by intervening layers of substantially impermeable material, the ramping well bore traversing through the plurality of layers of subterranean deposits and substantially impermeable material.

5. The subterranean drainage pattern of claim 4, wherein one or more of the plurality of layers of subterranean deposits comprise a coal seam.

6. The subterranean drainage pattern of claim 1, wherein each of the first plurality of ramping well bores mirrors one of the second plurality of ramping well bores.

7. The subterranean drainage pattern of claim 1, wherein each lateral well bore comprises:

a radiused portion extending from the main well bore, the radiused portion comprising a radius of curvature that is substantially equal to a radius of curvature of the radiused portion each of the first plurality of ramping well bores; and

an elongated portion extending from the radiused portion to the periphery of the area.

8. The subterranean drainage pattern of claim 1, wherein each ramping well bore comprises:

a radiused portion extending from the main well bore; and

an elongated portion extending from the radiused portion toward the boundary.

9. A method for drilling a subterranean drainage pattern for accessing an area of a subterranean zone comprising:

drilling a main well bore extending from a surface well bore located at a first end of the area to a second end of the area, the main well bore traversing a substantially horizontal plane, wherein the length of each of the lateral well bore progressively shortens as a distance between a respective lateral well bore and the surface well bore increases;

drilling a first plurality of lateral well bores extending in spaced apart relation to each other from the main well bore to the periphery of the area on a first side portion of the main well bore, wherein the length of each of the lateral well bore progressively shortens as a distance between a respective lateral well bore and the surface well bore increases;

drilling a second plurality of lateral well bores extending in spaced apart relation to each other from the main well bore to a periphery of the area on a second, opposite side portion of the main well bore; and

drilling a first plurality of ramping well bores extending in spaced apart relation to each other from an upper portion of the main well bore, the first plurality of ramping well bores extending in a substantially vertical plane toward an upper boundary of the subterranean zone; and

drilling a second plurality of ramping well bores extending in spaced apart relation to each other from a lower portion of the main well bore, the second plurality of ramping well bores extending in a substantially vertical plane toward a lower boundary of the subterranean zone.

10. The method of claim 9, wherein the subterranean zone comprises a single layer of hydrocarbons.

11. The method of claim 10, wherein the single layer comprises a coal seam.

12. The method of claim 9, wherein the subterranean zone comprises a plurality of layers of subterranean deposits separated by intervening layers of substantially impermeable material, the ramping well bore traversing through the plurality of layers of subterranean deposits and substantially impermeable material.

13. The method of claim 12, wherein at least one of the plurality of layers of subterranean deposits comprises a coal seam.

14. The method of claim 9, wherein each of the first plurality of ramping well bores mirrors one of the second plurality of ramping well bores.

15. The method of claim 9, wherein drilling each lateral well bore comprises:

drilling a radiused portion extending from the main well bore, the radiused portion comprising a radius of curvature that is substantially equal to a radius of curvature of the radiused portion each of the first plurality of ramping well bores; and

drilling an elongated portion extending from the radiused portion to the periphery of the area.

16. The method of claim 9, wherein drilling each ramping well bore comprises:

drilling a radiused portion coupling extending from the main well bore; and

drilling an elongated portion extending from the radiused portion toward the boundary.

17. A subterranean drainage pattern for accessing an area of a subterranean zone comprising:

a main well bore extending from a surface well bore located at a first end of the area to a second end of the area, the main well bore traversing a substantially horizontal plane;

a first plurality of lateral well bores extending in spaced apart relation to each other from the main well bore to the periphery of the area on a first side portion of the main well bore, wherein the length of each of the lateral well bore progressively shortens as a distance between a respective lateral well bore and the surface well bore increases;

a second plurality of lateral well bores extending in spaced apart relation to each other from the main well bore to a periphery of the area on a second, opposite side portion of the main well bore, wherein the length of each of the lateral well bore progressively shortens as a distance between a respective lateral well bore and the surface well bore increases; and

a first plurality of ramping well bores extending in spaced apart relation to each other from an upper portion of at least one of the first plurality of lateral well bores the first plurality of ramping well bores extending in a substantially vertical plane toward an upper boundary of the subterranean zone; and

a second plurality of ramping well bores extending in spaced apart relation to each other from a lower portion of the at least one of the first plurality of lateral well bores, the second plurality of ramping well bores extending in a substantially vertical plane toward a lower boundary of the subterranean zone.

18. The subterranean drainage pattern of claim 17, wherein the subterranean zone comprises a single layer of hydrocarbons.

19. The subterranean drainage pattern of claim 18, wherein the single layer comprises a coal seam.

20. The subterranean drainage pattern of claim 17, wherein the subterranean zone comprises a plurality of layers of subterranean deposits separated by intervening layers of substantially impermeable material, the ramping well bore traversing through the plurality of layers of subterranean deposits and substantially impermeable material.

21. The subterranean drainage pattern of claim 20, wherein at least one of the plurality of layers of subterranean deposits comprises a coal seam.

22. The subterranean drainage pattern of claim 17, wherein each of the first plurality of ramping well bores mirrors one of the second plurality of ramping well bores.

23. The subterranean drainage pattern of claim 17, wherein each lateral well bore comprises:

a radiused portion extending from the main well bore, the radiused portion comprising a radius of curvature that is substantially equal to a radius of curvature of the radiused portion each of the first plurality of ramping well bores; and

an elongated portion extending from the radiused portion to the periphery of the area.

24. The subterranean drainage pattern of claim 17, wherein each ramping well bore comprises:

a radiused portion extending from the main well bore; and

an elongated portion extending from the radiused portion toward the boundary.

25. A method for drilling a subterranean drainage pattern for accessing an area of a subterranean zone comprising:

drilling a main well bore extending from a surface well bore located at a first end of the area to a second end of the area, the main well bore traversing a substantially horizontal plane;

drilling a first plurality of lateral well bores extending in spaced apart relation to each other from the main well bore to the periphery of the area on a first side portion of the main well bore, wherein the length of each of the lateral well bore progressively shortens as a distance between a respective lateral well bore and the surface well bore increases;

drilling a second plurality of lateral well bores extending in spaced apart relation to each other from the main well bore to a periphery of the area on a second, opposite side portion of the main well bore, wherein the length of each of the lateral well bore progressively shortens as a distance between a respective lateral well bore and the surface well bore increases; and

drilling a first plurality of ramping well bores extending in spaced apart relation to each other from an upper portion of at least one of the first plurality of lateral well bores, the first plurality of ramping well bores extending toward an upper boundary of the subterranean zone; and

drilling a second plurality of ramping well bores extending in spaced apart relation to each other from a lower portion of the at least one of the first plurality of lateral well bores, the second plurality of ramping well bores extending toward a lower boundary of the subterranean zone.

26. The method of claim 25, wherein the subterranean zone comprises a single layer of hydrocarbons.

27. The method of claim 26, wherein the single layer comprises a coal seam.

28. The method of claim 25, wherein the subterranean zone comprises a plurality of layers of subterranean deposits separated by intervening layers of substantially impermeable material, the ramping well bore traversing through the plurality of layers of subterranean deposits and substantially impermeable material.

29. The method of claim 28, wherein at least one of the plurality of layers of subterranean deposits comprises a coal seam.

30. The method of claim 25, wherein each of the first plurality of ramping well bores mirrors one of the second plurality of ramping well bores.

31. The method of claim 25, wherein drilling each lateral well bore comprises:

drilling a radiused portion extending from the main well bore, the radiused portion comprising a radius of curvature that is substantially equal to a radius of curvature of the radiused portion each of the first plurality of ramping well bores; and

drilling an elongated portion extending from the radiused portion to the periphery of the area.

32. The method of claim 25, where in drilling each ramping well bore comprises:

drilling a radiused portion extending from the main well bore; and

drilling an elongated portion extending from the radiused portion toward the boundary.